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The reaction forces at the tungsten support probes of a platinum microwire are determined by numerical analysis for different push-pull sliding velocities and contact pressures. The Finite Element Analysis (FEA) tool ANSYS Workbench is used to evaluate the contact stresses, reaction forces and deformations of the platinum microwire. The nonlinear contact analysis and contact formulations are implemented to ensure that the platinum microwire maintained contact with the tungsten support probes during push-pull sliding motion, and transfer frictional forces between contact surfaces without penetration and separation. The reaction forces at the support probes are found independent of the sliding velocity of the platinum microwire and vary with normal contact pressure. The results found in the numerical analysis are validated through experimental works. Due to the tiny size, the nonlinearity of contacts and indeterminate supports criteria, it is difficult to determine the reaction forces at the supports of a sliding microwire by conventional mechanics. The method of the numerical analysis of the sliding microwire presented in this paper can be used to determine the reaction forces of other microstructures, validate the experimental results, as well as to evaluate total disturbance forces in the microstructures where relative motion exists; which are important for the proper design and failure analysis of the MEMS devices and microstructures.

Fluid flow in the lid driven cavity is a well-known phenomenon in the realm of fluid flow and heat transfer. Different cavity shapes such as square, circular, trapezoidal, and hexagonal have already been studied. However, most of the parametric analyses have previously been done using one specific cavity shape design. The present study intends to generalize the cavity design for a larger range of applications starting from the selection of cavity form due to the enhancement of heat transfer inside that selected cavity for different boundary conditions. Numerical studies using a finite element solver have been carried out to investigate the physics of fluid flow and heat transmission in a cavity where a wall of the enclosure is moving. In this research, the average Nusselt number for six distinct shaped lid-driven cavities is studied (e.g., square, rhombus, circular, rounded rectangular, trapezoidal and hexagonal). The hexagonal-shaped cavity has the largest Nusselt number of all of them. The heat transfer increases by about 90% when the cavity shape changes from square to hexagonal at Ri = 0.1, Pr = 7, Re = 100, Ha = 30, and ? = 60°. To boost the heat transfer rate, magnetohydrodynamics (MHD) mixed convection in a lid-driven cavity with an imposed angled magnetic field was investigated. Richardson number, Reynolds number, Prandtl number, Hartmann number, and magnetic inclination angle within the enclosure are shown in terms of streamline plots, isothermal contour profiles, and Nusselt number. Through parametric investigations of cavity shapes, inclined magnetic fields, and other boundary conditions, the current research intends to improve the Nusselt number within the cavities.

The current research is directed to observe, assess, and evaluate the physical, mechanical, and thermal properties of the fabricated composite. In this study, rattan and bamboo fiber have been used...

The effects of fiber orientation and volume fraction on the mechanical and thermal properties of laminated jute reinforced polyester composite are investigated. The composite sheets of thickness 4....

Researches have already been focused on renewable fibre as one of the reinforcements in composite materials during past few years. In this research, locally available inexpensive natural fibres ter...

Complexity in deriving the differential equations of temperature and pressure responses in pneumatic systems arises from the nonlinearity of the parameters inside the control volume. These parameters include flow characteristics, mass flow rate, change of temperature and pressure, and the heat transfer through walls. The latter is usually neglected in favor of simplicity, and the precise modeling of temperature and pressure responses is being sacrificed. This paper discusses the effect of heat transfer through walls on pressure and temperature responses of the pneumatic system by solving the nonlinear differential equations of temperature and pressure for two thermal conditions—with and without considering the heat transfer through walls for various ambient temperatures. It is found that the pressure and temperature responses are more precise with considering heat transfer through walls. Additionally, the temperature and pressure responses have been validated through experimental work.

In this paper, an experimental study of a concentric staggered annular fin with radial outlets and a staggered rectangular fin with lateral outlets for steady-state natural convection, and forced convection is presented. The objective of this work is to investigate the effect of shape, profile and arrangement of the fins in heat transfer with minimum blockage ratio, stagnation, and pressure drop. In this regard, the two different shapes of fins are designed with the same material, identical extended surface area, width, and thickness; and studied experimentally with identical thermal load and boundary conditions, as well as identical flow characteristics. In case of forced convection, the orientation of the base-plate of the fins is kept perpendicular to the direction of flow to achieve velocity vectors parallel to the fin surfaces. The overall heat transfer coefficient, fin efficiency, effectiveness, and temperature distribution of both fins are compared for different base-plate's temperature of the fins and different free stream air velocity; and also for natural convection. It is found that the shape of the fins has a significant effect on heat transfer, especially in the case of forced convection. Though both fins are performed almost the same in natural convection, the concentric staggered annular fin with radial outlets performed better in forced convection. It is concluded that the concentric staggered annular fin with radial outlets can be used in the practical field instead of the conventional rectangular fin, particularly for forced convection., {"references":["Nguyen, H., A. Aziz (1992), \"Heat transfer from convecting-radiating fins of different profile shapes\", Wärme-und Stoffübertragung,. Volume 27, Issue 2, pp. 67−72.","Hong, S.K., D.-H. Rhee, H.H. Cho (2005), \"Effects of fin shapes and arrangements on heat transfer for impingement/effusion cooling with crossflow\", in ASME Turbo Expo 2005: Power for Land, Sea, and Air. American Society of Mechanical Engineers.","Kraus, A.D. (1988), \"Sixty-five years of extended surface technology (1922–1987)\", Applied Mechanics Reviews, Volume 41, Issue 9, pp. 321-364.","Lorenzini, G., S. Moretti (2017), \"Numerical analysis on heat removal from Y-shaped fins: Efficiency and volume occupied for a new approach to performance optimisation\", International Journal of Thermal Sciences, Volume 46, Issue 6, pp. 573−579.","Reddy, R.S.k., et al., \"Thermal Analysis of Pin Fin with Different Shape Forms using ANSYS\", International Journal of Engineering Science and Computing (IJESC), Volume 7, Issue 5.","A/K Abu-Hijleh, B. (2003), \"Numerical simulation of forced convection heat transfer from a cylinder with high conductivity radial fins in cross-flow. International Journal of Thermal Sciences\", Volume 42, Issue 8, pp. 741−748.","Kim, Y.H., et al. (2004), \"Effects of fin and tube alignment on the heat transfer performance of finned-tube heat exchangers with large fin pitch\"","Asadi, M., R.H. Khoshkho (2013), \"Temperature distribution along a constant cross sectional area fin\", International Journal of Mechanics and Applications, Volume 3, Issue 5, pp. 131−137.","Starner, K., H. McManus (1963), \"An experimental investigation of free-convection heat transfer from rectangular-fin arrays\", Journal of Heat Transfer, Volume 85, Isssue 3, pp. 273−277.","İzci, T., M. Koz, A. Koşar (2015), \"The effect of micro pin-fin shape on thermal and hydraulic performance of micro pin-fin heat sinks\", Heat Transfer Engineering, Volume 36, Issue 17, pp. 1447−1457."]}

A leaf spring is a simple form of spring commonly used for the suspension system in heavy duty vehicles which is originally called laminated or carriage spring. It performs the isolation task in transferring the vibration due to road irregularities to the passenger's body or goods transported on it. The advantage of leaf spring over helical spring is that the ends of the spring have been guided along a definite path as it deflect to act as a structural member in addition to an energy absorbing device. Increasing competition and innovations in the automobile sector, tends to modify the existing products with new or advanced material products. To improve the performance of the suspension system, many modifications have been taken place overtime but the recent innovations imply parabolic leaf spring and application of composite materials, as the composite materials have high strength-to-weight ratio compared to the conventional steels. The present work attempts to analyze the comparison between the conventional steel (AISI1030) leaf spring and the composite (Carbon/Epoxy) leaf spring with respect to static and fatigue analysis. Here static analysis determines the safe stress, deformation and corresponding pay load and also studies the behavior of structures under practical conditions. The research also focuses on fatigue analysis to determine its life cycle and also to observe its fatigue failure characteristics. The model of the leaf spring has been carried out into the CAD software. The analysis of the steel leaf spring has been divided into theoretical, experimental and simulation sections. The simulation of steel leaf spring has been validated with the theoretical and the experimental results. Further simulation has been done for composite leaf spring by FEA software. Finally, the result shows that the composite leaf spring has better load carrying capacity in reduced weight, and better fatigue behavior rather than the conventional steel material for the leaf spring.

This prospective study was carried out in the coronary care unit, department of cardiology in National Institute of Cardiovascular Diseases, Dhaka, during the period of July 2007 to December 2007. Sixty consecutive patients with acute myocardial infarction below 40 years of age, subjected to coronary angiogram were enrolled with some inclusion and exclusion criteria to evaluate the risk factors and pattern of coronary artery disease in young patients with myocardial infraction. The age range of the study patients was 14-39 years with mean age of 29.07 ± 3.45 years. 56 (93.33%) patients were male and 4 (6.67%) patients were female. It was evident that commonest risk factor was smoking 73.33%. Other risk factors include dyslipidaemia 53.33%, hypertension 41.67%, hyperhomocystinaemia 25%, family history of IHD in 13.33% patients and diabetes 6.67%. Coronary artery diseases present in 91.67% patients. 72.73% patients had single vessel disease, 18.18% patients had double vessel disease and 9.09% patients had triple vessel disease. Left anterior descending artery involved in 80% patients, left circumflex artery involved in 27.27% patients and right coronary artery involved in 29.09% patients. In conclusion, acute myocardial infraction in young patients is most commonly seen in males and most frequent risk factor is smoking. Majority patients has single vessel disease and most frequently involve vessel is LAD.  University Heart Journal Vol.4(1) January 2008

This study was conducted at the Dhaka Medical College (DMC) morgue among 100 postmortem cases of Road Traffic Accident (RTA) victims over a period of one year. The objective of this study was to find out incidences of head injury among the RTA victims along with other injuries and also to overview the present situation of RTA in the country. Out of 100 cases, 64% were male and 36% female. The highest incidence of RTA (28%) was observed among the age group 31 to 40 years. The highest number of victims were pedestrians (68%). Considering recorded causality by type of collision, hit pedestrian was the most common (39%), followed by head on collision (20%). Regarding injury pattern in different parts of body, all the victims had multiple abrasion and bruise, 90% had laceration, 78% had injury to brain and 77% victims had injury to abdominal organs like liver and spleen. In the skull, Linear/fissured fracture was the commonest type of fracture (36%), followed by comminuted fracture (18%). Temporal bone was observed most prone to be fractured (23%), followed by parietal bone (17%). Most of the victims had subdural haemorrhage (43%), followed by sub arachnoid haemorrhage (36%). Key words: Road traffic accident, head injury, postmortem. DOI: 10.3329/jafmc.v5i2.4579 JAFMC Bangladesh Vol.5(2) (December) 2009, pp.24-28